Abstract

Neurovascular compression takes place when the cranial nerve is compressed by a blood vessel within the root entry/exit zone - REZ. We may then observe a pathological stimulation or hypersensitivity of a given nerve, which may lie at the base of various pathological syndromes. Trigeminal neuralgia is often caused by the compression within REZ of nerve V. The compression of nerve VII may lead to hemifacial spasm, nerve VIII - to vertigo and hypoacusia, nerve IX - to glossopharyngeal neuralgia, and nerve X - to arterial hypertension. As neurosurgical treatment of neurovascular compression became possible, a vital role in the qualification of patients for surgical procedures is played by imaging techniques. Magnetic resonance imaging (MRI) remains a basic method, for which no adequate examination protocol concerning the discussed pathology has been formulated so far. In order to evaluate the usefulness of new examination protocol, it was applied during the investigation of 106 patients directed to the magnetic resonance laboratory at the Medical University in Gdansk with a probable neurovascular vasospasm. During the MRI examination of head, a standard T2-SE sequence of the whole brain was used in order to exclude lesions other than neurovascular compression. Then, MRTA vascular sequence and T2-SE were performed in the plane modified to an examined nerve, of 1 mm slice. We assessed the correspondence between obtained results and a clinical picture as well as the length of the visualised nerve, having assumed that a correct examination plane was the one with the whole intracranial segment of a given nerve being visible. Nerves VII, VIII, IX and X were visualised in one examination plane, if it was parallel to optic nerve in its retrobulbar and intra-conoid course. Nerve V was optimally visualised on an axial plane, at an angle of 15°to the above mentioned plane. The examination protocol used in the present study seems to visualise optimally the intracranial segments of cranial nerves as well as the location of neurovascular compression.

Keywords: Trigeminal Neuralgia, Vertigo, glossopharyngeal neuralgia, arterial hypertension, root entry/exit zone, Hemifacial Spasm, Magnetic Resonance Imaging, neurovascular compression